Immunofluorescence analysis of tumour sections from p38γ−/− and p38δ−/− mice compared to WT mice showed no differences in the percentage of BrdU-positive cells (Figure 1F) and in cells positive for phosphorylated STAT3 (signal transducer and activator of transcription 3) (Figure 1G), which is essential for keratinocyte proliferation and neoplastic transformation. Here, STAT3 is linked to neoplasm.